Marks: 5M, 6M

Year: Dec2014, Dec2015, Dec2013, May2014

Difficulty: Medium

Cascade method of refrigeration is used for production of low temperature refrigeration such as that maintained in applications like alloy manufacturing, liquefaction of gases, blood storage etc.

This system uses multiple refrigerants with progressively lower boiling points in a series of single unit refrigeration as shown in figure.

The high temperature cascade uses high boiling point refrigerant such as NH3 or R-12, whereas low temperature cascade uses low B.P. refrigerant such as CO2 or R-13.Intermediate temperature ‘tc1=te2’ is also called as ‘coupling temperature’